From the past, there has been used a stapler that binds binding-sheets by means of a metal-made staple (needle). In case of binding paper-sheets by using such a stapler by means of the metal-made staple, there sometimes happens a case in which it is requested to separate the paper-sheets and the staple when the paper-sheets are processed by a paper shredder or for the reason of recycling. Also, in view of the safety problem, it is not preferable to bind documents used in a work section handling food articles by means of a metal-made staple.
Also, differently from the above description, there have been proposed staples each formed by a soft raw material of paper or the like (for example, see Japanese Patent Application Publication No. H11-347966). The staples disclosed in the Japanese Patent Application Publication No. H11-347966 are ones formed by a soft raw material of paper or the like and interlinked with them being shaped into a shape in which both the edges thereof are bent beforehand to one direction. The staples disclosed in the Japanese Patent Application Publication No. H11-347966 are ones that bind the binding sheets by passing both the leg portions thereof through notches provided at the binding sheets by a cutter and then, by bending them along the binding sheets to bond them mutually.